Variant and uint64

[Peter Lameijn]

Here it is. (Bit messy, it's only a test.) Size, TotalCylinders and TotalSectors are UINT64. It's for enumerating USB storage devices.

' ========================================================================================
' WMI example - Retrieving Disk information
' ========================================================================================

#Compile Exe
#Dim All
#Include "win32api.inc"
#Include "TB_WMILIB.INC"    ' // WMI helper functions
                            ' see [url]http://www.powerbasic.com/support/pbforums/showpost.php?p=171374&postcount=3[/url]

' ========================================================================================
' Main
' ========================================================================================
Function PBMain

   Local hr As Long                   ' // HRESULT
   Local oServices As Dispatch        ' // Services object
   Local vServices As Variant         ' // Services object reference
   Local oItems As Dispatch           ' // Generic collection object
   Local vItems As Variant            ' // Generic collection object reference
   Local oItem As Dispatch            ' // Generic item object
   Local vItem As Variant             ' // Generic item object reference
   Local penum As Dword               ' // Collection's enumerator reference
   Local vCount As Variant            ' // Number of items in the collection
   Local vVar As Variant              ' // General purpose variant
   Local vRes As Variant              ' // General purpose variant
   Local i As Long                    ' // Loop counter
   Local x As Long                    ' // Loop counter
   Local Result As Long
   Local Tmp As String
   Local Disp As String
   Dim vArray(0) As Variant           ' // General purpose array of variants


   ' // Connect to WMI using a moniker
   hr = WmiGetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\cimv2", vServices)
   If hr <> %S_Ok Then GoTo Terminate
   Set oServices = vServices
   vServices = Empty
   If IsFalse IsObject(oServices) Then GoTo Terminate

   ' // Execute a query to get a reference to the collection of running processes
   vVar = "SELECT * FROM Win32_DiskDrive WHERE InterfaceType='USB'"
   Object Call oServices.ExecQuery(vVar) To vItems
   If ObjResult Then GoTo Terminate
   Set oItems = vItems
   vItems = Empty
   If IsFalse IsObject(oItems) Then GoTo Terminate

   ' // Retrieve the number of items in the collection
   Object Get oItems.Count To vCount

   ' // Retrieve a reference to the collection's enumerator
   hr = Wmi_NewEnum(ObjPtr(oItems), penum)
   If hr <> %S_Ok Or penum = %NULL Then GoTo Terminate

   ' // Iterate throught the collection of objects.
   For i = 1 To Variant#(vCount)
      ' // Retrieve a reference to the next object in the collection
      hr = WmiEnum_NextItem(penum, vItem)
      If hr <> %S_Ok Then Exit For
      Set oItem = vItem
      If IsFalse IsObject(oItem) Then Exit For
      '------------------------------------------------------------------------
      Object Get oItem.MediaType To vRes
      Disp = $Cr & "MediaType: "  & $Tab & Variant$(vRes)
      '------------------------------------------------------------------------
      Object Get oItem.VolumeSerialNumber To vRes
      Disp = Disp & $Cr & "VolumeSerialNumber: "  & $Tab & Variant$(vRes)
      '------------------------------------------------------------------------
      Object Get oItem.Model To vRes
      Disp = Disp & $Cr & "Model: "  & $Tab & Variant$(vRes)
      '------------------------------------------------------------------------
      Object Get oItem.PNPDeviceID To vRes
      Disp = Disp & $Cr & "PNP Device ID: "  & $Tab & Variant$(vRes)
      '------------------------------------------------------------------------
      Object Get oItem.DeviceID To vRes
      Disp = Disp & $Cr & "Device ID: "  & $Tab & Variant$(vRes)
      '------------------------------------------------------------------------
      Object Get oItem.Size To vRes
      Disp = Disp & $Cr & "Size: "  & $Tab & Variant$(Vres)'Format$(Variant#(Vres))
      '------------------------------------------------------------------------
      Object Get oItem.TotalCylinders To vRes
      Disp = Disp & $Cr & "Cylinders: "  & $Tab & Variant$(vRes) 'Format$(Variant#(vRes))
      '------------------------------------------------------------------------
      Object Get oItem.TotalHeads To vRes
      Disp = Disp & $Cr & "Heads: "  & $Tab & Format$(Variant#(vRes))
      '------------------------------------------------------------------------
      Object Get oItem.TotalSectors To vRes
      Disp = Disp & $Cr & "Sectors: "  & $Tab & Variant$(vRes) 'Format$(Variant#(vRes))
      '------------------------------------------------------------------------
      Object Get oItem.BytesPerSector To vRes
      Disp = Disp & $Cr & "BytesPerSector: "  & $Tab & Format$(Variant#(vRes))
      '------------------------------------------------------------------------
      Set oItem = Nothing
      MsgBox Disp,, Tmp
   Next

   WmiRelease penum
   If IsObject(oItems) Then Set oItems = Nothing
Terminate:
   If IsObject(oServices) Then Set oServices = Nothing
End Function
' ========================================================================================

[Michael Mattias]

Strange enough, when I use VariantVT it returns NULL string (%VT_NULL)
But if I use Variant$ on any UINT64 member of Win32_DiskDrive, the correct value is returned...

VT_NULL does NOT describe a "null string", it describes NULL. (Nothing, no value of any type, not even what type it isn't.)

VARIANT$() cannot possibly return the 'correct value' of a VT_UI8 (UINT64): UINT64 is numeric; VARIANT$() returns a string.

Here's an idea: Let's try, "SHOW FAILING CODE." (I probably should have thought of that earlier.)


MCM

[Peter Lameijn]

Strange enough, when I use VariantVT it returns NULL string (%VT_NULL)
But if I use Variant$ on any UINT64 member of Win32_DiskDrive, the correct value is returned...

[Michael Mattias]

VARIANT#(VT_UI8 var) Works here... (PB/Win 9.0.1)

FUNCTION PBMAIN () AS LONG

    LOCAL StStart AS SYSTEMTIME, STEnd AS SYSTEMTIME
    
    CALL TestVUint64()
    EXIT FUNCTION


END FUNCTION

FUNCTION TestVUint64() AS LONG
  LOCAL pV  AS VARIANTAPI PTR, v AS VARIANT
  
  LOCAL Q AS QUAD, pQ AS QUAD PTR
  
  LET V = EMPTY   '  intialize
  PV    = VARPTR (V) ' pointer
  
  @pV.vt  = %VT_UI8    ' unint 64
  pQ      = VARPTR (@pV.VD)
  Q       = 12345&&
  @pq     = Q
  
  
  ' get variant#() value from intrinsic function
  
  Q  =  VARIANT#(V)
  MSGBOX FORMAT$(Q)

' hmm, try with bit 63 set...
  LET Q = -12345&&
  @pq   = Q
  Q     = VARIANT#(V)
  MSGBOX FORMAT$(Q),, "With value -12345"

  
    
END FUNCTION

.. so you will HAVE to show your failing code if you are having problems.


MCM

[Michael Mattias]

Purpose
Return the numeric value contained in a Variant variable.

Syntax
numericvar = VARIANT#(vrntvar)

Remarks
The value returned by VARIANT# may be any range from BYTE to DOUBLE/QUAD/CURRENCY, depending upon the internal representation used within the Variant

A uint64 will be out of range for a QUAD when bit 63 is set. While I'm surprised that VARIANT#() does not (allegedly, code not shown) just return the 64 bits in a sign-agnostic manner... wait a minute, I don't believe it doesn't. Let me write some test code and see what happens.

(While I am doing this, you should make a note that VARIANT#() also does not handle VT_DECIMAL types, but there is code here to handle that for you). (Yes, I have submitted a new feature suggestion for same).

MCM

[Peter Lameijn]

How do I retrieve an unsigned quad (UINT64) from a Variant? I tried several things and they all return '0'...
For instance Variant#(MyVariant) also returns '0'. Do I need to use VariantVT() somehow?

[edit]
For some reason, if I use Variant$ on places where an uint64 is expected, all goes well...
Is this a MS docu error, or does it have another cause? (Happens with Win32_DiskDrive )
[/edit]